Apparatus for casting metal



p 9, 1969 E. Q. SYLVESTER 3,465,810

APPARATUS FOR CASTING METAL Filed Dec. 4. 1967 have 1102" EdyuuudSy/zesi Q I v Z/WJAAZ%ZQ United States Patent U.S. Cl. 164259 2 ClaimsABSTRACT OF THE DISCLOSURE Molten metal is poured into a mold and duringsolidification of the metal within the mold an inert gas, such as argon,is bubbled upwardly through the metal.

It has been the practice to cast metal by pressure pouring and bycontinuous casting. If a rimming grade steel is desired, it has been thepractice to vacuum degas the melt in order to control the oxygen contentof the melt to reduce the rimming action during cooling of the moltenmetal in a pressure casting mold. Vacuum degassing of the melt has alsobeen used to reduce the oxygen content for ingot casting as well ascontinuous casting. Vacuum degassing of the molten metal requiresexpensive equipment with the result that rimmed steel, produced by sucha process is expensive.

It is, therefore, an object of this invention to provide a method andapparatus for casting metal.

A further object of this invention is to provide a method and apparatusfor the casting of rimmed steel.

It is a further object of this invention to provide a method andapparatus for the casting of rimmed steel slabs, billets, blooms andother similar articles without the attendant increase in cost of theprior art process.

These and other advantages and objects of this invention will becomeapparent from a reading of the following detailed description of thisinvention, when taken in conjunction with the accompanying drawings,wherein:

FIGURE 1 is a perspective view of the apparatus of this invention; and

FIGURE 2 is a perspective view of a portion of the apparatus of thisinvention, which portion is capable of introducing an inert gas into themold cavity.

Referring now to the drawings, reference numeral denotes the pouringtube of a conventional pressure pouring apparatus (not shown). Thepouring tube 10 is open at its upper end 12 for communication with aningate assembly 14. The ingate assembly is secured to the cast ironbottom block 16 of a vertical slab mold 18. The ingate assembly 14 isprovided with a central aperture 20 having inserted therein a ceramicsleeve 22, the bore 24 of which is in open communication with the bore26 of the pouring tube 10. Also positioned in and forming a part of theingate assembly 14 is a slide cut-off plate 28 having a bore 30 whichplate 28 slides in a recess 29 in the ingate assembly 14. A ceramicinsert 32 is positioned within the bore 30 of the slide cut-ofi plate 28and is provided with a bore 34 of the same internal diameter as theinternal diameter of the sleeve 22.

The mold 18 consists of a pair of graphite side blocks 36, a pair ofcast iron end blocks 38, the bottom block 16 and a cast iron riser 40.Only one side block 36 has been shown, it being understood that theother side block 36 is of identical construction. The side blocks 36,end blocks 38, bottom block 16 and riser 40 form therebetween a slabmolding cavity 42. The bottom block 16 is provided with a centralaperture '44 of the same internal diameter as the internal diameter ofthe insert 32 and is in open communication therewith. Preferably, thebottom block 16 is provided with a frustoconical cavity 46 communicatingwith the mold cavity 42.

Referring now to FIGURE 2 for a more complete showing of the slidecut-off plate 28 and associated structure, wherein the plate 28 isprovided with a second aperture or bore 48. A ceramic sleeve 50 ispositioned snugly within the bore 48 and retains a porous plug 52 ofsuitable refractory material such as a spinel. Means such as a pipe 54are provided to supply inert gas such as boron to the porous plug 52.

The slide plate is moved from its position wherein sleeve 32 is alignedas shown in FIGURE 2 to its position wherein the porous plug 52 isaligned with the aperture 44 by a piston rod 56 operatively connected toan air or hydraulic cylinder 58.

In operation, the mold 18 is positioned over the pouring tube 10 of aconventional pressure pouring apparatus (not shown). The slide cut-01fplate 28 is positioned with the ceramic sleeve 32 in alignment with thebore 26 of the pouring tube and the aperture 44 of the bottom block 16.Molten metal is forced upwardly by the conventional pressure pouringmethod through the pouring tube into the mold cavity 42 until the cavityhas been filled. The piston 58 is actuated to move the slide cutoifplate from its position in FIGURE 1 to its position wherein the porousplug is aligned with the aperture 44 of the bottom block 16. The airpressure is shut off and the inert gas supply is started which forcesthe inert gas through line 54, and the porous plug 52 upwardly into thestill molten central portion of the casting. The inert gas bubblesupwardly through the casting thereby removing deleterious substancessuch as hydrogen from the melt. It also deoxidizes the melt.

Since the inert gas bubbles in from the bottom, rimming action isobtained throughout the slab rather than only in a portion of the slabin ingot pouring. This process will result in interanl cooling of themelt which will reduce the shrinkage and the solidification time.

In the preferred embodiment of this invention, the top 60 of the mold 18is covered with a light refractory brick or asbestos to prevent theintroduction of oxygen into the mold during the inert gas introduction.

It can be seen from the foregoing that this method and apparatus willproduce an improved product. It should be understood that variousmodifications may be made in the invention without departing from thespirit and scope of the following claims.

I claim:

1. An apparatus for casting metal articles comprising a mold having acavity of the configuration of the article to be formed, means forforcing molten metal upwardly into the mold, an ingate assembly having apassageway to provide communication between said means and said mold, aslide plate forming a part of said ingate assembly, said slide platebeing provided with an aperture and a porous plug alignable with saidpassageway, said porous plug being in open communication with inert gassupply means, and means for aligning said aperture With said passagewayduring filling of the mold and for aligning said plug duringsolidification of said article.

2. An apparatus according to claim 1 wherein said mold is a verticalmold comprising a pair of cast iron end blocks, a cast iron bottomblock, a cast iron riser and a pair of graphite side blocks.

References Cited UNITED STATES PATENTS Burkhardt 164-66 X Sylvesterl64-66 Goedecke et a1. 164-56 X Sylvester 164-66 Bonis et al. 164-5510/1967 Buehl et a1 164-66 X 11/1967 Wentzell 164-68 X 2/1968 Bonis eta1 164-259 X 12/1958 Dunn 164-259 3/ 1895 Casgrain 164-306 FOREIGNPATENTS 6/ 1961 Italy.

2/1963 Japan.

U.S. Cl. X.R.

